Total internal reflection lens with integrated lamp cover

Abstract

A total internal reflection (TIR) lens has an integrated lamp cover adapted to a lamp of a desired form factor (e.g., PAR-38). The size and shape of the TIR lens can be adapted to optimize the light output of the lamp with little regard to the desired form factor. The integrated lamp cover can extend the front surface of the TIR lens in a direction transverse from the optical axis.

1. A lens assembly comprising:
 a total internal reflection (TIR) body member having a first end, a second end opposite the first end, and an outer surface, the TIR body member being substantially cylindrically symmetric with respect to an optical axis, the outer surface having a tapered shape such that the TIR body member is wider at the second end than at the first end, the tapered shape providing total internal reflection to direct light from a light source position near the first end toward the second end; and 
 a cover member disposed at the second end of the TIR body member and integral with the TIR body member, the cover member having a width in a direction transverse to the optical axis that is greater than a widest diameter of the TIR body member and a thickness in a direction along the optical axis that is less than a thickness of the TIR body member. 
 
     
     
       2. The lens assembly of  claim 1  wherein the thickness of the cover member is not more than about 10% of a total thickness of the lens assembly. 
     
     
       3. The lens assembly of  claim 2  wherein the thickness of the cover member is between about 5% and about 10% of a total thickness of the lens assembly. 
     
     
       4. The lens assembly of  claim 1  wherein the widest diameter of the TIR body member is not more than about 40% of the width of the cover member. 
     
     
       5. The lens assembly of  claim 4  wherein the widest diameter of the TIR body member is between about 25% and about 40% of the width of the cover member. 
     
     
       6. The lens assembly of  claim 1  wherein the TIR body member further includes an inner sidewall defining a central open channel that extends longitudinally from the first end to the second end, the central open channel being centered on and substantially symmetric with respect to the optical axis. 
     
     
       7. The lens assembly of  claim 6  wherein the central open channel extends through the cover member. 
     
     
       8. The lens assembly of  claim 7  wherein the inner sidewall and the outer surface of the TIR body member are shaped so as to provide mixing of light from a plurality of light emitting diodes within a light source. 
     
     
       9. The lens assembly of  claim 7  wherein the inner sidewall is tapered at an angle between about 1° and about 5° relative to the optical axis, such that the open channel is wider at the second end than at the first end. 
     
     
       10. The lens assembly of  claim 1  wherein the TIR body member and the cover member are made of poly(methylmethacrylate). 
     
     
       11. The lens assembly of  claim 1  further comprising a flange disposed near a peripheral edge of the front end face member and extending rearwardly therefrom. 
     
     
       12. The lens assembly of  claim 11  further comprising a plurality of mounting posts extending rearwardly from the flange. 
     
     
       13. The lens assembly of  claim 12  wherein the flange and the mounting posts are formed integrally with the cover member and the TIR body member. 
     
     
       14. The lens assembly of  claim 1  wherein the cover member has a plurality of microlenses disposed in a front surface thereof. 
     
     
       15. The lens assembly of  claim 1  wherein a front surface of the cover member is circular. 
     
     
       16. The lens assembly of  claim 15  further comprising a plurality of mounting posts extending rearward from a region near a peripheral edge of the cover member.